Isolating children from one of their parents can have many implications. Forefront among these can simply be the economic hardship caused from supporting a family alone, but problems can go much further. As the child grows, they may find themselves questioning their roots, and wondering about their other parent, and when they learn that their other parent has been kept from them, they may resent the parent they grew up with.
Keeping a child away from the other parent can backfire in serious and permanent ways. If the other parent feels that the situation will not resolve itself, they have the legal right to bring the matter before the court to enforce the existing court order regarding the parenting plan and their visitation rights.